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Grenzen der konzentrationsmessung eines hoch frequenz titrimeters mit einer frequenz von etwa 130 MHz.
A 130
Journal
of Electroanalytical
Chemistry
Vol. 1
impurities) in the dimethylformamide caused salicylic acid to behave like a weak acid, while in very pure dimethylformamide its titration curve was characteristic of a strong acid. The strongest bases, caesium methoxide and rubidium methoxide do produce more acute end-point angles (in the titration curves), however the difference in basicity as compared to potassium or sodium methoxide does not justify their ordinary use. The high-frequency method is useful for titrations if a coloured impurity is present and if the compound or its product is coloured, but offers no advantage when indicators are available. Ja. Inc. [4221 NEW CONDUCTOMETRIC METHOD FOR TITRATION OF SURFACE ACTIVE AGENTS SUCH AS ALKYLARYLSULPHONATES, ALKYLSULPHONATES AND ALKYL SULPHATES WITH P-TOLUIDINE HYDROCHLORIDE. H. Niewiadomski, W. Zwierzykowskl and M. Ploszynskl. (Dept. of Fat Technology, Politechnika, Gdaiisk, Poland.) Chemia Anal. , 4 (1959) 995. The conductivity changes which occurred during the titration of surface active agents with p - toluidine hydrochloride were used to detect the end-point of the titration, At this point a minimum was observed. For various agents different amounts of titrant were used per mole of titrate. The method is quick and independent of the concentration of titrant and titrate, the pH and the presence of inorganic salts. Ad. Hu. [423] GRENZEN DER KONZENTRATIONSMESSUNG EINESHOCHFREQUENZTITRIMETERS MIT EINER FREQUENZ VON ETWA 130 MHz. E. Pungor und L. Balazs. (Institut filr anorg. u. analytische Chemie, EGtv&s-UniversitXt, Budapest, Ungarn. ) Mikrochim. Acta, 1 (1960) 118. Die unteren Konzentrationgrenzen der Durchfilhrbarkeit von Saure-Basen-u. Flllungstitrationen mit dem bei 130 MHz arbeitenden Hochfrequenztitrimeter wurden untersuoht. Es wurde festgestellt, dass die untere Grenze der Bestimmungsmijglichkeit bei Salzsaure 1, bei Essigsaure 20, bei Chlorid 2, und bei Sulfat 10 ng/ml betragt. Beztlglich der Wahl der Titerflilssigkeit halten die Verfasser die Anwendung solcher Reagentien fiir wichtig, bei denen die Richtungstangente im Aquivalenzpunkt mijglichst ihr Vorzeichen lindert. Ed. Bro. 14241 HIGH FREQUENCY TITRATION OF A13+ WITH Ba(OH)2. E. Pungor and E. E. Zapp. (Institute of Inorganic and Analytical Chemistry, Eiitvijs University, Budapest, Hungary.) Bull. sot. chim. France, (1960) 121. The weakly acidic solution, containing 0.2 - 20 mg Al is titrated with a standard solution of 0.1 N Ba(OH)2, In the presence of sulphate it is advisable to wait about 5 min after the first additions in order to effectuate the separation of BaS04. The additionof the reagent is stopped when the titration curve becomes horizontal. The acidity is known from the position of the discontinuity in the titration curve. The Ba(OH)2 is now added continuously until there is a distinct increase of the admittance. About half of the amount added after neutralisation is now added in excess which causes the aluminium hydroxide to dissolve as aluminate, The excess of base is back-titrated with a standard solution of 0.1 N acetic acid. In the presence of sulphate the titration rate should be slow to prevent losses by adsorption on the precipitate. Carbon dioxide should be excluded. 4.00 ml 0.1 N~Ba(OH), is equivalent to 2.70.mg Al. A correction can be made. for Fe(III) in amounts less than 5% after spectrophotometrical estimation of its content.
Journal
of Electroanalytical
Chemistry
Vol. 1
impurities) in the dimethylformamide caused salicylic acid to behave like a weak acid, while in very pure dimethylformamide its titration curve was characteristic of a strong acid. The strongest bases, caesium methoxide and rubidium methoxide do produce more acute end-point angles (in the titration curves), however the difference in basicity as compared to potassium or sodium methoxide does not justify their ordinary use. The high-frequency method is useful for titrations if a coloured impurity is present and if the compound or its product is coloured, but offers no advantage when indicators are available. Ja. Inc. [4221 NEW CONDUCTOMETRIC METHOD FOR TITRATION OF SURFACE ACTIVE AGENTS SUCH AS ALKYLARYLSULPHONATES, ALKYLSULPHONATES AND ALKYL SULPHATES WITH P-TOLUIDINE HYDROCHLORIDE. H. Niewiadomski, W. Zwierzykowskl and M. Ploszynskl. (Dept. of Fat Technology, Politechnika, Gdaiisk, Poland.) Chemia Anal. , 4 (1959) 995. The conductivity changes which occurred during the titration of surface active agents with p - toluidine hydrochloride were used to detect the end-point of the titration, At this point a minimum was observed. For various agents different amounts of titrant were used per mole of titrate. The method is quick and independent of the concentration of titrant and titrate, the pH and the presence of inorganic salts. Ad. Hu. [423] GRENZEN DER KONZENTRATIONSMESSUNG EINESHOCHFREQUENZTITRIMETERS MIT EINER FREQUENZ VON ETWA 130 MHz. E. Pungor und L. Balazs. (Institut filr anorg. u. analytische Chemie, EGtv&s-UniversitXt, Budapest, Ungarn. ) Mikrochim. Acta, 1 (1960) 118. Die unteren Konzentrationgrenzen der Durchfilhrbarkeit von Saure-Basen-u. Flllungstitrationen mit dem bei 130 MHz arbeitenden Hochfrequenztitrimeter wurden untersuoht. Es wurde festgestellt, dass die untere Grenze der Bestimmungsmijglichkeit bei Salzsaure 1, bei Essigsaure 20, bei Chlorid 2, und bei Sulfat 10 ng/ml betragt. Beztlglich der Wahl der Titerflilssigkeit halten die Verfasser die Anwendung solcher Reagentien fiir wichtig, bei denen die Richtungstangente im Aquivalenzpunkt mijglichst ihr Vorzeichen lindert. Ed. Bro. 14241 HIGH FREQUENCY TITRATION OF A13+ WITH Ba(OH)2. E. Pungor and E. E. Zapp. (Institute of Inorganic and Analytical Chemistry, Eiitvijs University, Budapest, Hungary.) Bull. sot. chim. France, (1960) 121. The weakly acidic solution, containing 0.2 - 20 mg Al is titrated with a standard solution of 0.1 N Ba(OH)2, In the presence of sulphate it is advisable to wait about 5 min after the first additions in order to effectuate the separation of BaS04. The additionof the reagent is stopped when the titration curve becomes horizontal. The acidity is known from the position of the discontinuity in the titration curve. The Ba(OH)2 is now added continuously until there is a distinct increase of the admittance. About half of the amount added after neutralisation is now added in excess which causes the aluminium hydroxide to dissolve as aluminate, The excess of base is back-titrated with a standard solution of 0.1 N acetic acid. In the presence of sulphate the titration rate should be slow to prevent losses by adsorption on the precipitate. Carbon dioxide should be excluded. 4.00 ml 0.1 N~Ba(OH), is equivalent to 2.70.mg Al. A correction can be made. for Fe(III) in amounts less than 5% after spectrophotometrical estimation of its content.